Spain’s civil war (1936 to 1939) provided a nasty foretaste of World War II, with fascists battling communists, and foreign dictators supporting their favored ideologies. Meanwhile, volunteers flocked in from other countries, usually to fight for the left-wing Spanish government. (The communists had the more energetic propaganda.)

Among the American volunteers was Frank Tinker, an outstanding pilot and a good squadron leader, though he never really learned the language of the Spaniards and Russians he took into combat. The language barrier hardly mattered; there was no radio in Tinker’s Polikarpov fighter.

Tinker was credited with more than enough aerial victories to be designated an ace. Most of his targets were German and Italian biplanes, but they also included two Messerschmitt Bf 109s, one of the great aerial weapons of World War II. Oddly, Smith and Hall (the latter an Air & Space/Smithsonian contributing editor) make no attempt to verify his combat claims, which almost certainly are exaggerated.

Though Tinker achieved the “five down” of a fighter ace, the customary glory escaped him. Working as a mercenary pilot, though, had made him a modestly wealthy man by the time he headed home. A wider war was brewing in which his talents would have been highly valued. Alas, Tinker died in a hotel in Little Rock, Arkansas, of a gunshot wound that at the time was ruled a suicide, though his biographers make a good case that he was murdered.

Except for a few omissions, this is a splendid biography.

Daniel Ford wrote about another band of mercenary pilots, Flying Tigers: Claire Chennault and His American Volunteers, 1941–1942 (Harper Collins-Smithsonian Books, 2007).